U.S. patent number 7,037,112 [Application Number 10/324,365] was granted by the patent office on 2006-05-02 for virtual arm for measurement of humidity, temperature, and water vapor transmission rate in materials.
This patent grant is currently assigned to Kimberly-Clark Worldwide, Inc.. Invention is credited to Rick Beal, Jason Cohen, Frank F. Kromenaker, Patrick R. Lord, Nancy Puckett, Timothy Schmitz, Arvinder Singh, Martha L. Tate, Audra S. Wright.
United States Patent |
7,037,112 |
Lord , et al. |
May 2, 2006 |
**Please see images for:
( Certificate of Correction ) ** |
Virtual arm for measurement of humidity, temperature, and water
vapor transmission rate in materials
Abstract
A device is provided for simulating a human skin microclimate
and for measuring conditions such as temperature and humidity in
the simulated microclimate. The microclimate is formed, for
example, with fluids, gases and/or heat in a chamber of the device
or between a surface of the device and a material disposed about
the surface. In one aspect, a sensor is placed in the chamber to
sense the microclimate. Methods of using the device and measuring
microclimate conditions are also provided.
Inventors: |
Lord; Patrick R. (Appleton,
WI), Schmitz; Timothy (Menasha, WI), Singh; Arvinder
(Neenah, WI), Kromenaker; Frank F. (Appleton, WI), Beal;
Rick (Oshkosh, WI), Cohen; Jason (Appleton, WI),
Tate; Martha L. (Atlanta, GA), Wright; Audra S.
(Woodstock, GA), Puckett; Nancy (Roswell, GA) |
Assignee: |
Kimberly-Clark Worldwide, Inc.
(Neenah, WI)
|
Family
ID: |
32593402 |
Appl.
No.: |
10/324,365 |
Filed: |
December 20, 2002 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040121294 A1 |
Jun 24, 2004 |
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Current U.S.
Class: |
434/262; 434/268;
434/272 |
Current CPC
Class: |
G09B
23/28 (20130101) |
Current International
Class: |
G09B
23/28 (20060101) |
Field of
Search: |
;434/126,262,267,268,272,295,328,329 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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803714 |
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Jan 1969 |
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CA |
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2272182 |
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May 1994 |
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GB |
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Primary Examiner: Fernstrom; Kurt
Attorney, Agent or Firm: Dority & Manning, P.A.
Claims
That which is claimed is:
1. A device for simulating human skin microclimate and for
measuring conditions in a simulated microclimate, the device
comprising: an object having a surface, a plurality of apertures
therethrough and a chamber therein, a first one of the apertures
configured to pass a fluid into communication between the surface
and a material disposed about the surface and the first one of the
apertures; a heater attachable to the object configured to heat the
object, the heated object and the fluid cooperable to produce a
microclimate; and a sensor disposed in the chamber configured to
sense the microclimate.
2. The device as in claim 1, wherein the object is selected from
the group consisting of a lower-torso mannequin, an upper-torso
mannequin, a full-body mannequin, a mannequin forearm, a mannequin
hand, a mannequin foot, a mannequin leg, a mannequin head and
combinations thereof.
3. The device as in claim 2, wherein the mannequin forearm is
cylindrically shaped.
4. The device as in claim 3, wherein the cylindrically shaped
mannequin forearm defines a circumference from between 2 inches to
80 inches.
5. The device as in claim 1, wherein the object is selected from
the group consisting of a metal, a glass, a resin, an epoxy, a
polymer, and combinations thereof.
6. The device as in claim 5, wherein the metal is selected from the
group consisting of an aluminum, a steel, a tin, a brass, an iron,
and combinations thereof.
7. The device as in claim 1, wherein the object defines a slot
therethrough, the slot extending from the surface of the object to
the chamber.
8. The device as in claim 7, wherein the chamber is a void area
defined in the object configured for occupation by one of the
fluid, a plurality of fluids, a gas from one of the fluid or
plurality of fluids, and combinations thereof.
9. The device as in claim 8, wherein the chamber is from 0.25
inches to 4.0 inches in diameter and from 2 inches to 5 inches in
length.
10. The device as in claim 7, wherein the slot is elongated, the
elongated slot substantially parallel to the chamber.
11. The device as in claim 7, wherein the slot is from 0.0625
inches to 3.0 inches wide and from 2 inches to 5 inches in
length.
12. The device as in claim 7, wherein the slot comprises a
plurality of slots disposed about the surface of the object
substantially parallel to each other, the plurality of slots spaced
apart from each other from 0.05 inches to 0.5 inches.
13. The device as in claim 1, wherein the heater comprises a
plurality of heater cartridges configured for insertion in the
object via respective apertures of the plurality of apertures.
14. The device as in claim 13, wherein the plurality of heater
cartridges is configured to produce heat from between 80.degree. F.
to 120.degree. F. to heat the object to a normal human body
temperature.
15. The device as in claim 1, wherein the heater heats the
object.
16. The device as in claim 15, wherein the object, the surface, the
chamber, or combinations thereof exhibit a uniform temperature.
17. The device as in claim 1, wherein the microclimate is produced
in one of the chamber, the plurality of apertures, proximate a side
of the material disposed apart from the surface, proximate another
side of the material facing the surface, about a substrate attached
to the surface, and combinations thereof.
18. The device as in claim 1, wherein the microclimate includes one
of a temperature, a relative humidity, an absolute humidity, a
fluid, a gas and combinations thereof.
19. The device as in claim 1, wherein the first one of the
apertures is from 0.1875 inches to 0.5 of an inch in diameter with
a tubing terminating proximate the first one of the apertures, the
tubing having an outlet configured to deliver the fluid through the
first one of the apertures to insult the material.
20. The device as in claim 19, further comprising a fluid delivery
device in communication with the tubing proximate a second one of
the apertures, the fluid delivery device and the tubing configured
to cooperably insult a predetermined amount of the fluid through
the first one of the apertures into the material.
21. The device as in claim 20, wherein the fluid delivery device is
a computer controlled pump.
22. The device as in claim 19, wherein the tubing is made from one
of the group consisting of glass, metal, plastic, rubber, and
combinations thereof.
23. The device as in claim 19, wherein the first one of the
apertures and the tubing outlet cooperably simulate an opening
selected from the group consisting of a tear duct, a urethra, a
pore, a body cavity, and combinations thereof.
24. The device as in claim 1, further comprising a substrate
removably attached to the surface, the material disposed about the
substrate, the fluid transmittable into communication proximate the
substrate and the material, the substrate configured for
evaluation.
25. The device as in claim 24, wherein the substrate is selected
from the group consisting of a medical grade collagen film, a
collagen disposed in a sausage casing, a chamois, a cellulose film,
a cultured skin substrate, a bioengineered skin, a living skin
sample, a dead skin sample and combinations thereof.
26. The device as in claim 1, wherein the material is selected from
the group consisting of disposable or non-disposable diapers,
disposable or non-disposable adult incontinence products,
disposable or non-disposable feminine products, disposable or
non-disposable nursing healthcare products, disposable or
non-disposable child training pants, disposable or non-disposable
face masks, disposable or non-disposable bandages, disposable or
non-disposable gloves, micro-porous film, stretchable film, latex
rubber, cotton gauze, bandage materials, carded webs, VFL, SBL,
SMS, spunbond, cellulose, absorbent composites and combinations
thereof.
27. The device as in claim 1, wherein the fluid is selected from
the group consisting of water, saline, synthetic or natural menses,
synthetic or natural urine, synthetic or natural BM, artificial or
natural breast milk, synthetic or natural blood, 0.9% sodium
chloride solution, colored solution, and combinations thereof.
28. The device as in claim 1, wherein the sensor is inserted into
the chamber via one of the apertures.
29. The device as in claim 1, wherein the sensor is one of an RH
probe, a temperature probe, a spectroscopic probe, a
chromatographic probe, a fiber optic waveguide, a video camera, a
CCTV camera, an IR camera and combinations thereof.
30. The device as in claim 1, further comprising a measuring device
configured to measure an exterior condition of the material by one
of capacitance, capacitive reactance, conductance, electrical
impedance, WVTR and TEWL.
31. The device as in claim 30, wherein the measuring device is a
TEWL probe configured to measure a water vapor transmission rate of
the material.
32. The device as in claim 1, further comprising a temperature
controller in controllable communication with the heater, the
temperature controller configured to sense a temperature of the
heated object and regulate the heater.
33. The device as in claim 32, wherein the temperature controller
includes a temperature sensor attachable to the object, the
temperature sensor configured to sense and communicate the
temperature of the heated object to the temperature controller.
34. The device as in claim 1, further comprising a base configured
for removable attachment to the object.
35. The device as in claim 34, wherein the object is adjustable
relative to the base.
36. A device for simulating a human skin microclimate and for
measuring conditions in a simulated microclimate, the device
comprising: an object having a surface with a material disposed
thereon; a heater attachable to the object and configured to heat
the object, the heated object and one of a fluid and a gas
cooperable to produce a microclimate proximate a void formed in the
object and the material; and a sensor disposed about the object,
the sensor configured to sense the microclimate proximate the
void.
37. The device as in claim 36, wherein the object is selected from
the group consisting of a lower-torso mannequin, an upper-torso
mannequin, a full-body mannequin, a mannequin forearm, a mannequin
hand, a mannequin foot, a mannequin leg, a mannequin head and
combinations thereof.
38. The device as in claim 37, wherein the mannequin forearm is
cylindrically shaped.
39. The device as in claim 38, wherein the cylindrically shaped
mannequin forearm defines a circumference from between 2 inches to
80 inches.
40. The device as in claim 36, wherein the object is selected from
the group consisting of a metal, a glass, a resin, an epoxy, a
polymer, and combinations thereof.
41. The device as in claim 40, wherein the metal is selected from
the group consisting of an aluminum, a steel, a tin, a brass, an
iron, and combinations thereof.
42. The device as in claim 36, wherein the object defines the
microclimate between the object and the material.
43. The device as in claim 42, wherein the microclimate is disposed
in the void defined about the object and configured for occupation
by the fluid.
44. The device as in claim 43, wherein the void is defined by a
depression on the surface of the object.
45. The device as in claim 44, wherein the depression is 0.0625
inches to 3.0 inches wide and from 2 inches to 5 inches in
length.
46. The device as in claim 44, wherein the depression comprises a
plurality of depressions disposed about the surface of the object
substantially parallel to each other, the plurality of depressions
spaced apart from each other from 0.05 inches to 0.5 inches.
47. The device as in claim 36, further comprising a first aperture
therethrough the surface, the first aperture configured to pass the
fluid into communication between the surface and a material
disposed about the surface and the first aperture.
48. The device as in claim 36, wherein the heater comprises a
plurality of heater cartridges configured for insertion in the
object via respective apertures of the plurality of apertures.
49. The device as in claim 48, wherein the plurality of heater
cartridges is configured to produce heat from between 80.degree. F.
to 120.degree. F. to heat the object to a normal human body
temperature.
50. The device as in claim 36, wherein the heater heats the
object.
51. The device as in claim 50, wherein the object, the surface, the
chamber, or combinations thereof exhibit a uniform temperature.
52. The device as in claim 36, wherein the microclimate includes
one of a temperature, a relative humidity, an absolute humidity,
and combinations thereof.
53. The device as in claim 47, wherein the first aperture is from
0.1875 inches to 0.5 of an inch in diameter with a tubing
terminating proximate the first aperture, the tubing having an
outlet configured to deliver the fluid through the first aperture
to insult the material.
54. The device as in claim 53, wherein the tubing is inserted into
the object via a second aperture.
55. The device as in claim 54, further comprising a fluid delivery
device in communication with the tubing proximate the second
aperture, the fluid delivery device and the tubing configured to
cooperably insult a predetermined amount of the fluid through the
first aperture into the material.
56. The device as in claim 55, wherein the fluid delivery device is
a computer controlled pump.
57. The device as in claim 53, wherein the tubing is made from one
of the group consisting of glass, metal, plastic, rubber, and
combinations thereof.
58. The device as in claim 53, wherein the first aperture and the
tubing outlet cooperably simulate an opening selected from the
group consisting of a tear duct, a urethra, a pore, a body cavity,
and combinations thereof.
59. The device as in claim 36, further comprising a substrate
removably attached to the surface, the material disposed about the
substrate, the fluid transmittable into communication proximate the
substrate and the material, the substrate configured for
evaluation.
60. The device as in claim 59, wherein the substrate is selected
from the group consisting of a medical grade collagen film, a
collagen disposed in a sausage casing, a chamois, a cellulose film,
a cultured skin substrate, a bioengineered skin, a living skin
sample, a dead skin sample and combinations thereof.
61. The device as in claim 36, wherein the material is selected
from the group consisting of disposable or non-disposable diapers,
disposable or non-disposable adult incontinence products,
disposable or non-disposable feminine products, disposable or
non-disposable nursing healthcare products, disposable or
non-disposable child training pants, disposable or non-disposable
face masks, disposable or non-disposable bandages, disposable or
non-disposable gloves, micro-porous film, stretchable film, latex
rubber, cotton gauze, bandage materials, carded webs, VFL, SBL,
SMS, spunbond, cellulose, absorbent composites and combinations
thereof.
62. The device as in claim 36, wherein the fluid is selected from
the group consisting of water, saline, synthetic menses, synthetic
urine, synthetic BM, artificial breast milk, blood, 0.9% sodium
chloride solution, colored solution, and combinations thereof.
63. The device as in claim 36, wherein the sensor is inserted
proximate the microclimate.
64. The device as in claim 36, wherein the sensor is one of an RH
probe, a temperature probe, a spectroscopy probe, a chromatographic
probe, a fiber optic waveguide, a video camera, a CCTV camera, an
IR camera and combinations thereof.
65. The device as in claim 36, further comprising a measuring
device configured to measure an exterior condition of the material
by one of capacitance, conductance, electrical impedance, WVTR and
TEWL.
66. The device as in claim 65, wherein the measuring device is a
TEWL probe configured to measure a water vapor transmission rate of
the material.
67. The device as in claim 36, further comprising a temperature
controller in controllable communication the heater, the
temperature controller configured to sense a temperature of the
heated object and regulate the heater.
68. The device as in claim 67, wherein the temperature controller
includes a temperature sensor attachable to the object, the
temperature sensor configured to sense and communicate the
temperature of the heated object to the temperature controller.
69. The device as in claim 36, further comprising a base configured
for removable attachment to the object.
70. The device as in claim 69, wherein the object is adjustable
relative to the base.
71. A method of simulating a human skin microclimate and for
measuring conditions in a simulated microclimate, the method
comprising the steps of: providing an object with an aperture
therethrough and a sensor configured to sense a condition of a
microclimate; at least partially covering the object with a
material; heating the object to a normal human body temperature;
insulting the material with a fluid from a fluid delivery device;
and assessing the condition of the microclimate with the sensor,
the microclimate interposed between the surface and the
material.
72. The method as in claim 71, wherein the object is selected from
the group consisting of a lower-torso mannequin, an upper-torso
mannequin, a full-body mannequin, a mannequin forearm, a mannequin
hand, a mannequin foot, a mannequin head, and combinations
thereof.
73. The method as in claim 71, further comprising the step of
warming the fluid before insulting the material.
74. The method as in claim 71, wherein the heating step is
performed by a plurality of heater cartridges configured for
insertion in the object via a plurality of apertures.
75. The method as in claim 74, wherein the plurality of heater
cartridges are configured to produce heat from between 80.degree.
F. to 120.degree. F. to heat the surface.
76. The method as in claim 71, wherein the material is an absorbent
article selected from the group consisting of disposable or
non-disposable diapers, disposable or non-disposable adult
incontinence products, disposable or non-disposable feminine
products, nursing healthcare products, disposable or non-disposable
child training pants, face masks, bandages, gloves and combinations
thereof.
77. The method as in claim 71, wherein the fluid is selected from
the group consisting of water, saline, synthetic menses, synthetic
urine, synthetic BM, artificial breast milk, blood, sodium chloride
solution, colored solution, and combinations thereof.
78. The method as in claim 71, further comprising the step of
controlling a temperature of the heated surface via a temperature
controller in electrical communication with the surface.
79. The method as in claim 71, further comprising the step of
evaluating the material by one of capacitance, conductance,
capacitive reactance, electrical impedance, WVTR and TEWL.
80. The method as in claim 79, further comprising a measuring
device with a TEWL probe, the TEWL probe disposable on an exterior
of the material spaced apart from the surface of the object.
81. The method as in claim 71, further comprising the step of
monitoring the microclimate with a monitor, the monitor configured
to selectively record the condition including a temperature and a
humidity.
Description
BACKGROUND OF THE INVENTION
Absorbent articles such as diapers, adult incontinence garments,
feminine care products, child training pants, pull-ups, bandages,
gloves and similar products that directly contact skin are well
known. A disposable absorbent article is typically composed of a
top layer that is adjacent to a user's body and a back layer that
faces the clothing of the user. An absorbent material is located
between the top layer and the bottom layer. The top layer permits a
liquid from the user to move through the top layer toward the back
layer. The back layer does not allow liquid to be transferred from
the inside of the absorbent article onto the user's clothing. The
absorbent material absorbs the liquid and keeps the skin dry.
During normal operation after a fluid is discharged from a user,
the fluid will flow through the top layer and be absorbed by the
absorbent material. The absorbent material is designed to absorb,
redistribute, and store the fluid until the absorbent article is
discarded. In some instances, however, fluid may return from the
absorbent material to once again contact the user's skin. Fluid
return can occur, for instance, if the absorbent material cannot
sufficiently absorb the fluid due to the composition of the
absorbent material. Unabsorbed liquid undesirably results in
over-hydration of the contacted skin and in turn, increases a
chance of skin irritation to the user. In addition to being an
irritant, excessive moisture on the user's skin can cause, among
other things, the growth of microorganisms that can lead to the
onset of rashes or infection.
Various tests exist for measuring performance and suitability of
absorbent materials to prevent the foregoing problems. Known tests
include capacitance, capacitive reactance, conductance, electrical
impedance, and/or evaporative or Trans-Epidermal Water Loss (TEWL)
evaluations. Typically, these tests measure fluid absorbency, fluid
leakage, and other criteria of the materials for use in absorbent
articles.
By way of example, the Adult Forearm Test or "armband" test is
conventionally used to evaluate the effectiveness of disposable
diapers to keep the skin dry. In the armband test, changes in skin
surface hydration are measured by evaporimetry or TEWL evaluation.
To maintain a healthy and moisture-balanced skin, the TEWL readings
between un-diapered and diapered skin should not differ
significantly. One variation of the armband test uses pre-loaded
patches from diapers placed on an adult volar forearm, and
differences in skin surface hydration between cloth diapers and
disposable paper diapers have been noted.
Another armband test uses an intact diaper wrapped around the
forearm. Physiological saline is injected into the diaper at a rate
and volume that represent normal urination by a child.
Post-occlusion measurements are made after one hour, and
measurements of skin hydration are made by computerized
evaporimetry or by electrical conductance.
The above and other common tests have been used extensively for
evaluating skin hydration of covered or diapered skin. It would be
advantageous to have a bench top instrument that produces results
similar to the TEWL test to reduce for instance high variability
found in conventional tests.
BRIEF SUMMARY OF THE INVENTION
In general, the present invention is directed to a bench top
instrument for evaluating materials quickly, efficiently, and cost
effectively. In particular, a virtual arm is provided to evaluate
the microclimate and hydration of the substrate covered by the test
material. The virtual arm produces results similar to the TEWL test
and is also used for determining microclimate conditions in the
materials. The component parts of the invention are simple,
reliable, and economical to manufacture and use.
In one aspect of the invention, a metallic cylinder is provided to
simulate an adult forearm for rapidly evaluating a material for
further evaluation, possibly on human subjects. The arm
incorporates a fluid injection port to simulate a urethra, a sweat
gland, a pore, and the like. A simulated skin substrate is placed
on a portion of the arm proximate the fluid injection port. The
prototype material is wrapped about the simulated skin substrate
and the fluid injection port. Saline or other simulated
physiological fluid is insulted into the prototype material. After
a predetermined time, the prototype material is removed and the
skin is evaluated for dryness.
In another aspect of the invention, a mechanical arm incorporates a
fluid injection port to simulate a sweat gland, a pore, a urethra
and the like. A material is wrapped about the arm and the fluid
injection port. Saline or other simulated physiological fluid is
insulted into the material. The material is held in place on the
arm under a controlled temperature condition to allow determination
of a microclimate in the material.
The foregoing aspects of the present invention enable rapid
pre-screening of material at relatively low cost without many of
the variables found in conventional screening devices and methods.
Other aspects and advantages of the invention will be apparent from
the following description and the attached drawings, or can be
learned through practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects and advantages of the present invention
are apparent from the detailed description below and in combination
with the drawings in which:
FIG. 1 is a front elevational view of an apparatus in accordance
with an aspect of the invention;
FIG. 2 is a perspective view of a portion of the apparatus as in
FIG. 1, particularly showing an exemplary virtual arm;
FIG. 3 is a partial end view of the virtual arm as in FIG. 2;
FIG. 4 is a partial perspective view of a portion of the virtual
arm as in FIG. 2, particularly showing an exemplary chamber;
FIG. 5a is a cross-sectional end-view of a conventional evaluation
apparatus;
FIG. 5b is a cross-sectional end-view of the apparatus as in FIG. 4
taken along lines Vb--Vb;
FIG. 5c is a cross-sectional end-view of another embodiment
according to the invention;
FIG. 6 is a perspective view of the apparatus in accordance with a
further aspect of the invention, particularly showing a material
being evaluated;
FIG. 7 is a graph showing a relative humidity comparison between a
virtual arm and a clinical arm;
FIG. 8 is a graph showing a temperature comparison between a
virtual arm and a clinical arm; and
FIG. 9 is a chart showing various trial reading comparing a virtual
arm and a clinical arm.
Repeat use of reference characters in the drawings and the detailed
description is intended to represent same or analogous features or
elements of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Definitions
As used herein, the terms "simulated," "artificial," "synthetic"
and like terms are used interchangeably to indicate manufactured
materials or objects, and in the case of substrates, dissected or
bio-engineered skin samples, unless otherwise indicated.
As used herein, the term "substrate" generally refers to a
work-piece designed to simulate human skin. The substrate can be
used directly as obtained from a living or dead source; from a
bioengineered, cultured, or manufactured product; and/or following
a pretreatment to modify a character of the substrate. For example,
the substrate can be derived from any biological source such as a
living/preserved skin sample from animal models including but not
limited to a pig, a monkey, a rat, a human cadaver and similar
sources. Examples of bioengineered or cultured sources include but
are not limited to a VITRO-SKIN.TM. or VITRO-CORNEUM.RTM. product
available from IMS Inc., Milford, Conn.; a TEST SKIN.TM. II product
available from Organogenesis Inc., Canton, Mass.; a SKINETHIC.RTM.
product available from Skinethic Tissue Culture Laboratories, Nice,
France; EpiDerm.TM. simulated human skin from Matek Corporation,
Ashland, Mass.; a medical grade collagen film; a collagen in a
sausage casing; a cellulose film; a chamois; a cultured or
bioengineered skin substrate; and similar materials.
By way of example, VITRO-SKIN.TM. contains protein and lipid
components and is designed to have topography, pH, critical surface
tension and ionic strength that mimic human skin. Its consistent
"N-19" topography and wetting properties across each sheet are
optimized to mimic relatively smooth skin found on the human back.
Thus, testing done on VITRO-SKIN.TM. is generally more reproducible
than that performed on human skin. In comparison,
VITRO-CORNEUM.RTM. is a collagen-based substrate with properties
similar to human stratum corneum i.e., the outer layer of epidermis
of primarily dead skin cells. Specifically, VITRO-CORNEUM.RTM. is
designed to simulate the thickness, visco-elasticity and surface
properties of human stratum corneum. Another suitable simulated
skin is collagen in a sausage casing. The collagen/casing
arrangement is a cost-effective alternative for pre-screening
materials and does not have to be handled and stored as a
biological sample. An exemplary collagen film is available from
NATURIN GmbH, Weinhein, Germany, under the designation of COFF12224
with a basis weight of about 28 g/m.sup.2. Another exemplary
collagen film is available from Devro, Inc, Geneva, Ill., under the
designation of Cutisin.TM..
As used herein, the term "fluid" generally refers to a liquid,
exudate or any substance having fluid-like properties suitable for
simulating a physiological fluid. The fluid can be derived from any
biological source, such as a physiological fluid, including blood,
saliva, ocular lens fluid, cerebral spinal fluid, perspiration,
urine, simulated urine, bowel movements (BM), milk, ascites fluid,
synovial fluid, peritoneal fluid, amniotic fluid, menses fluid or
the like. The fluid can be pretreated prior to use, such as
preparing plasma from blood, diluting viscous fluid and the like.
Methods of treatment can involve filtration, distillation,
concentration, inactivation of interfering components, and the
addition of reagents. Moreover, in addition to real or simulated
physiological fluids, other liquid samples can be used, such as
water, food products, saline, a solution of 0.9% sodium chloride, a
colored solution, and the like to examine environmental or food
absorption performance of a material.
As used herein, the term "material" generally refers to a natural
or artificial product to be insulted with the fluid for evaluating
skin hydration of a material-covered skin. The material can be a
prototype material, a finished product, a competitor's product and
the like. Examples of a material include but are not limited to an
absorbent material, disposable or non-disposable diapers, diaper
systems, adult incontinence products, feminine products, nursing
healthcare products, child training products, bandages, gloves,
face masks, disposable or non-disposable gloves, microporous film,
stretchable film, latex rubber, cotton gauze, bandage materials,
carded webs, vertical filament stretch-bonded laminates (VFL),
spunbonded laminates (SBL), carriers with spunbond filaments or
fibers (SMS), cellulose, absorbent composites, or any other
material or garment used for contact with skin. Additionally, the
material can be a non-woven polymer material, an airlaid material,
a wet material, a dry material, a treated material, and any
disposable or non-disposable material.
As used herein, the term "microclimate" generally refers to an
environment found in any area/volume between the material to be
tested and the object upon which the material is attached. The
area/volume includes but is not limited to any cavity, depression,
void, chamber, or other area/volume between the material and the
object that forms an internal climate or microclimate between the
material and the object. For example, in one aspect herein, the
microclimate is formed in a chamber defined within a cylinder. In
another aspect, the microclimate is formed simply between a surface
of the material and a surface of the object.
Detailed Description
Detailed reference will now be made to the drawings in which
examples embodying the present invention are shown. The drawings
and detailed description provide a full and detailed written
description of the invention and the manner and process of making
and using it, so as to enable one skilled in the pertinent art to
make and use it. The drawings and detailed description also provide
the best mode of carrying out the invention. However, the examples
set forth herein are provided by way of explanation of the
invention and are not meant as limitations of the invention. The
present invention thus includes modifications and variations of the
following examples as come within the scope of the appended Claims
and their equivalents.
In general, the present invention is directed to an evaluation
apparatus for determining microclimate conditions in a material.
The evaluation apparatus is also used for evaluating the substrate
hydration covered by the test material. In particular, the present
invention employs a virtual arm as a bench top instrument that
produces results similar to the conventional TEWL test by
simulating characteristics of a human arm. These characteristics
include but are not limited to relative and absolute humidity,
temperature, and physical dimensions. In addition to TEWL, humidity
and temperature, the virtual arm allows determination of the
microclimate conditions in the material based on spectroscopy,
video, polymeric thin film sensors such as Electronic Nose, or
other invasive or noninvasive monitoring.
Referring to FIG. 1, one embodiment of a bench test device 10 is
shown having a virtual arm 12 mounted on a base or stand 14. The
arm 12 defines a plurality of apertures or slots 16, which in this
example cooperate to form an internal space or chamber 18 (see FIG.
4) in order to create a microclimate as will be described below.
The arm 12 as shown can be adjustably attached to the stand 14 for
ease of testing and is also connected to a controller 24, described
below, via an electrical connection 24a.
In this example, the arm 12 is formed of a metal such as aluminum.
Metal permits uniform heating of the arm 12 as described below.
Although the exemplary arm 12 is made of aluminum, which can be
anodized, other metals and materials such as steel, tin, brass,
iron, glass, acetyl-plastic, acrylic-plastic, an elastomeric
material, a high density polyethylene, or any other resin, epoxy or
polymer, composite materials and similar moldable materials may be
suitably used.
While the illustrated arm 12 is representative of a female forearm,
it is not intended as a limitation of the invention. For example,
the arm is about 2 inches to about 80 inches in circumference,
often about 10 inches. The circumference of the arm 12 can be
adjusted from about 2 inches to about 80 inches electronically,
hydraulically, pneumatically, manually, or otherwise in proportion
to the material M to be tested. For instance, the arm 12 may be
adjusted to about 3 to about 5 inches in circumference to test a
premature baby material M, or to about 80 inches in circumference
to test a large size adult undergarment. Additionally, the
exemplary arm 12 is about 10 inches to about 20 inches in length,
more particularly about 12 inches, to accommodate a wide variety of
materials M. It is contemplated that the arm 12 can be adjusted in
length electronically, hydraulically, pneumatically, manually, or
otherwise, for instance by telescoping, to accommodate the variety
of materials M.
FIG. 1 further shows a thermosensor 26 attached to a surface 12c of
the arm 12 and connected to the controller 24 via a thermosensor
feedback 26a. The thermosensor 26 can be attached to the arm 12 by
tape, snap-ons, hook and loop fastening systems, and the like in
order to monitor a temperature of the arm 12 generated by a heater
cartridge or heaters 22 (see FIG. 2). Specifically, the
thermosensor 26, via the thermosensor feedback 26a, communicates
the sensed temperature from the arm 12 to the controller 24 in
order for the controller 24 to adjust or regulate the temperature
within or about the arm 12 to maintain a constant, simulated,
normal human body temperature or skin surface temperature.
More particularly, as shown in FIG. 2, a perspective view of the
bench test device 10 clearly shows a plurality of heaters 22
inserted in an end 12a of the arm 12. The heaters 22 are connected
to the temperature controller 24 via the electrical connection 24a.
The controller 24 heats the heaters 22 from about 70.degree.
Fahrenheit (F.) to about 120.degree. F. to heat the arm 12. In this
example, the heaters 22 uniformly heat the aluminum surface 12c of
the arm 12 as well as the chamber 18 to about 85.degree. to
99.degree. F., usually to about 90.degree. F. A skin 38 is attached
to the heated surface 12c and is thereby heated to emulate normal
human skin. By heating the arm 12 and the skin 38 to normal human
skin temperature, TEWL and other measurements more closely reflect
measurements that derive from conventional tests. Further details
and example operations of the heater 22 and resulting measurements
are described in the exemplary procedures and exemplary results
sections below.
Also shown in FIG. 2 is an access hole 20a through which a sensor
28 is inserted into the chamber 18 of the arm 12. The sensor 28 is
a probe that measures temperature, relative humidity (Rh), and/or
absolute humidity. Furthermore, the sensor 28 may use a fiber optic
waveguide to monitor and record spectroscopic and/or
chromatographic data. The sensor 28 may further include
closed-circuit TV (CCTV), infrared (IR) and/or video capabilities.
An example operation of the sensor 28 is described in greater
detail below. Also as further described herein, a water vapor
transmission rate (WVTR) emanating from the material M can be taken
from the exterior of the material M while the material M is wrapped
about the surface 12c.
FIG. 3 shows a detailed perspective view of an end 12b of the arm
12. In this illustration, additional heaters 22 are shown inserted
in a heater hole 23 similar to the arrangement at the end 12a shown
in FIG. 2. Again, the heaters 22 at end 12b are connected to the
controller 24 via the electrical connection 24a to heat the surface
12c of the arm 12 and the chamber 18.
FIG. 3 further illustrates a fluid insult tube 30 connected to a
fluid delivery device 34. The fluid insult tube 30 is inserted into
the arm 12 via an access hole 20b. In this aspect of the invention,
the fluid delivery device 34 is a digital or computer controlled
pump that delivers a predetermined amount of fluid F through the
arm 12. Although any pump may generally be used, a Masterflex.RTM.
Computerized Water Pump, available from Cole-Parmer of Vernon
Hills, Ill., is a suitable fluid delivery device 34. The
Cole-Parmer Masterflex.RTM. Computerized Water Pump can be operated
via a Windows.RTM. Linkable Instrument Network (WINLIN) software
program to link multiple pumps and mixers in synchronized or
unsynchronized sequences of operation. The WINLIN program also
features: Flow calibration by volume, weight or flow reference
Multiple flow, volume and torque units Volumetrical or
gravimetrical dispensing Constant or ramped flow/speed control
It is to be noted that the digital or computer controlled fluid
delivery device 34 is provided by way of example only in FIG. 3. A
syringe (not shown) or other "off-line" device can be suitably used
to manually inject the fluid F in the material M. It is to be
further noted that the fluid insult tube 30 is shown in FIG. 3
inserted in the arm 12 via the access hole 20b by way of example
only and is not intended to limit the scope of the invention.
Although the exemplary arrangement ensures that external forces do
not disturb the fluid insult tube 30, the fluid insult tube 30 can
be inserted at various points in or on the arm 12 to insult the
material M. The fluid insult tube 30, for instance, can be arranged
externally to the arm 12, such as by taping the fluid insult tube
30 to the surface 12c, or elevated a predetermined distance from
the surface 12c without affecting operation of the fluid insult
tube 30.
FIG. 4 shows a detailed perspective view of the slots 16 and the
chamber 18 of the arm 12. The chamber 18 constitutes a void area of
the arm 12, which in this example includes an open area/volume
formed between a plurality of "fins" created between the slots 16.
The exemplary slots 16 are machined into the arm 12 approximately
in a center third portion of the arm 12, although the slots 16 can
be machined in any other portion of the arm 12.
In this aspect of the invention, the slots 16 are elongated from
about 2 inches to about 5 inches in length, more particularly about
4 inches long, and from about 0.0625 inches to about 3.0 inches
wide, more particularly about 0.1875 inches wide. Moreover, the
slots 16 are disposed about the surface 12c of the arm 12
substantially parallel to each other, and spaced apart from about
0.05 inches to about 0.5 inches, more particularly about 0.2 inches
to create the chamber 18. In this exemplary embodiment, the chamber
18 is from about 0.25 inches to about 4 inches in diameter and from
about 2 inches to about 5 inches in length.
The illustrated slots 16 are not limited to elongated, parallel
geometries as described in the foregoing aspect of the invention.
It is intended that the slots 16 have various sizes and shapes and
be disposed on the arm surface 12c in regular or irregular
relationship to each other, such as in uniform or non-uniform
patterns, periodic or aperiodic patterns. Additionally, the slots
16 may not extend into a center of the arm 12 to form the chamber
18. The slots 16 may be depressions with multiple or uniform depths
and have semi-hemispherical, rectangular, curvilinear or other
geometric shapes. In one aspect, the slots 16 are about 0.0625
inches to about 3.0 inches wide and from about 2 inches to about 5
inches in length. Therefore, it is to be understood that additional
or fewer slots 16, or various shapes and sizes of slots 16, will
affect an overall size or existence of the chamber 18.
One purpose of slots 16 is to allow temperature and humidity to be
measured within the microclimate created in the chamber 18. The
microclimate is formed when the fluid F and/or a gas created from
an evaporation of the fluid F enters the chamber 18. The dimensions
of the slots 16 are designed to minimize the volume of the chamber
18 in order to minimize the time for the microclimate to stabilize.
However, as will be described in an alternative embodiment below,
the slots 16 and chamber 18 are provided by way of example only and
not as a limitation of the invention. For instance, simply
attaching the material M to the arm 12 and forming a space or void
area between a surface of the material M and surface 12c of arm 12
is sufficient to create the microclimate.
FIG. 4 further shows the fluid insult tube 30 terminating at an
opening 30a at an aperture 20c in the arm 12 to create a fluid
insult point 32. In this aspect, the opening 30a of the tube 30 is
from about 0.1875 of an inch to about 0.5 of an inch to simulate
various fluid loading protocols. More particularly, in this aspect
the opening 30a is about 0.3125 of an inch for insulting the
material M with fluid F to simulate a urine load of a child. A
particular protocol associated with this exemplary opening 30a is
described in greater detail in the Experiment sections below.
However, it is to be understood that the opening 30a can vary in
size, number and placement on the arm 12 to simulate tear ducts,
pores, a urethra, vaginal openings, body cavities or other
orifices. Therefore, depending on the variations of opening 30a,
various other fluid loading protocols can be applied to model adult
perspiration, menses discharge, breast milk discharge, bleeding, or
other fluid excretions.
FIG. 4 also shows the substrate 38 as a small patch or square of
substrate relative to the opening 30a. Using VITRO-SKIN.TM. as the
substrate 38, for example, the inventors have found that by placing
the substrate 38 at various locations on the surface 12c of the arm
12 from the opening 30a better differentiates material M
differences. For example, research has shown that 6 centimeters
(cm) is an advantageous distance from the opening 30a to the
substrate 38. Although distances of about 0 cm to about 12 cm are
feasible, materials M may be difficult to differentiate using TEWL
measurements and skin 38 when the substrate 38, for example, is too
close to the opening 30a and is saturated by a surge of fluid
F.
FIG. 5a shows a standard human armband test with a diaper M wrapped
about the arm and external measurements being taken by a TEWL probe
T. In this example, the TEWL probe T measures real-time temperature
and/or humidity and water loss across two probes within the TEWL
probe T.
With reference to FIGS. 2-4 and 5b, the virtual arm 12 is shown
performing a test similar to that of FIG. 5a. More specifically,
FIG. 5b shows a TEWL probe 36 with temperature and humidity sensors
36a,b arranged on the outer area of the diaper M. The heaters 22
are shown in FIG. 5b inserted in the heater holes 23 to heat the
arm 12, its chamber 18 and/or the surface 12c to a normal human
body temperature. As briefly introduced, the temperature, humidity,
and/or Rh sensor 28 is inserted in the chamber 18 to correlate
external human arm TEWL tests to relative humidity (Rh) in the
chamber 18. The substrate 38 is attached to the surface 12c and the
material M is wrapped about the surface 12c. Similar to the TEWL
probe T in FIG. 5a, the sensors 36a,b sense evaporative water loss
from the outer area of the material M. More detailed examples of
this exemplary operation are described under the Experiment
sections below.
FIG. 5c shows an alternative embodiment of the bench test device,
generally indicated by the numeral 110. A virtual arm 112 is
provided in this aspect similar to the arm 12 described above.
However, the embodiment of FIG. 5c does not use elongated slots 16
to form a chamber 18. In this alternative aspect of the invention,
heaters (not shown but similar to heaters 22) are inserted in
heater holes 123 to heat the arm 112 similar to the foregoing
embodiment. A material M' such as a diaper is wrapped about a
surface 112c of the arm 112. TEWL, temperature and humidity
measurements, and the like are taken, also as previously
described.
By way of example operation, FIG. 6 shows the material M wrapped
about the arm 12 and attached by, for example, tape or hook and
loop fastening systems. The fluid delivery device 34 injects the
fluid F into the arm 12, while the controller 24, heats the heaters
22 to heat the arm 12 to the normal human body temperature,
described in greater detail above. The skin 38 (see, e.g., FIG. 4)
is disposed proximate the opening 30a at a predetermined distance
also as previously described. The fluid delivery device 34 delivers
the fluid F through the tube 30 via the opening 30a in accordance
with a predetermined fluid loading protocol into the material M.
After a predetermined time, TEWL or other evaluations of the
microclimate, the substrate 38, and the material M are made. Any
suitable monitor and/or recording device (not shown) can be
provided to selectively record a condition resulting from these
evaluations, including the temperature or the humidity, for
comparison to subsequent experiments.
The present invention may be better understood with reference to
the following Experiments and protocols.
I. Experiment Conducted on an Exemplary Embodiment of the
Invention
Results derived from an experiment conducted in accordance with one
exemplary embodiment of the present invention are as follows.
Experiment
In the following experiment, a diaper M was tested on the arm 12 as
illustrated in FIGS. 1-4, 5b, and 6. In this experiment, a Step 3
Ultra-Trim.RTM. diaper was used as the diaper M. The diaper M was
attached about the arm 12 proximate the slots 16 and opening 30a. A
digital pump 34, capable of less than 1 cubic centimeters per
minute (cc/min) to over 800 cc/min, was set to insult 60 cc/min of
simulated physiological fluid F in 12 seconds. Prior to wrapping
the diaper M on the arm 12, ambient conditions were recorded at
71.50.degree. F., 39.5 Rh. The arm 12 was warmed with the heaters
22 to a temperature of 90.degree. F. A human arm, as seen in FIG.
5a, was left unwrapped and differences in temperature and humidity
and the like were observed and recorded. Both the virtual arm 12
and the human arm were wrapped with the material M but not loaded
with fluid F. The material M was insulted with fluid F three times
and evaluated after 30-90 minutes.
Results
Tables 1-3 , respectively at FIGS. 7-9, show comparisons between
the virtual arm 12 and a human arm as in FIG. 5a. The first data
check after the fluid F was injected in the materials M resulted in
a lower Rh data reading, as seen in Table 1 , at FIG. 7. This was
attributed to the probe 28 not being placed in an insult area of
the human arm. The probe 28 was then moved to the insult area of
the human arm and a second data check was made after the second
insult of fluid F. A third check was completed after a third
injection of fluid F. A fourth check was completed after a fourth
injection of fluid F. The preliminary test results as shown in
Tables 1-3, indicate that the virtual arm 12 can maintain a
temperature and humidity similar to a real human arm.
II. Experiment Conducted on another Exemplary Embodiment of the
Invention
In accordance with another exemplary embodiment of the present
invention, results derived from a clinical TEWL study conducted on
20 subjects testing for commercially available diaper products are
as follows.
Experiment
The following test involved the recording of baseline readings on
the skins of the human subjects for TEWL and on the outside of dry
diapers for WVTR. After a saline F was added to the diaper M, Rh
and temperature readings were taken inside the diaper M using an
HM138 probe at 20, 40, and 60 minutes into the test. A final TEWL
measurement was also taken.
In a second test, the arm 12 was used instead of human subjects.
With a sample size of 10, a baseline WVTR reading was taken on the
outside of a dry diaper M applied to the arm 12. Rh/temperature and
WVTR readings were taken at 20, 40, and 60 minutes into the test
after saline F was added to the diaper M.
Results
Data from the clinical study was compared to the data in the
subsequent arm 12 study to see if TEWL correlated to Rh inside the
virtual arm 12. A correlation was found between WVTR on the human
subjects and WVTR on the virtual arm 12. Additionally, reduced
variability was noted in the data (lower standard deviation) for
numerous variables measured.
Based on the strong correlation between the foregoing comparisons
between human tests and the virtual arm 12 experiments and the
repeatability of the latter, the arm 12 is suitable for a variety
of uses and is not limited to the foregoing examples. For instance,
the arm 12 can be employed as a bench test for evaluating materials
for dryness and other related properties; for establishing
procedures for measuring dryness in materials; for evaluating
equipment used to measure dryness; for screening competitive
products; for performing other research and development and the
like.
While preferred embodiments of the invention have been shown and
described, those skilled in the art will recognize that other
changes and modifications may be made to the foregoing embodiments
without departing from the spirit and scope of the invention. For
example, specific shapes of various elements of the illustrated
embodiment may be altered to suit particular applications such as
shaping the arm 12 as a lower torso mannequin, an upper torso
mannequin, a full body mannequin, a mannequin forearm, a mannequin
hand, a mannequin foot, a mannequin head and various other portions
of a human body. It is intended to claim all such changes and
modifications as fall within the scope of the appended claims and
their equivalents.
* * * * *